stefangordon/ethproof

A node package for server-side proof of existence (with timestamping) on the Ethereum blockchain.

ethproof

This module helps you publish Proof Of Existence transactions on the Ethereum blockchain. These create a permanent record of a document hash at a specific date and time, allowing you to prove when it was originally written.

For example, you may use this technique to document an invention or intellectual property to verify in the future the date at which you first created it. The only information about your data which is stored on the chain is the documents SHA256 hash.

Install

npm install --save ethproof

Usage

ES6

import {hashDocument, publishProof} from 'ethproof'

const privateKeyHex = '774a1dee2b3a3d6c64c0e47124d3ac7522ae5c57e1fef1c4abb1b3dd63bffee6';
const destinationAddress = '44241d4e6a0fd2acff819478a87b7cdfe7963468';
const document = Buffer.from('Hello Crypto! ' + Math.random().toString());

const documentHash = hashDocument(document);
const txHash = publishProof(privateKeyHex, destinationAddress, documentHash);

ES5

var ethproof = require('ethproof');

var privateKeyHex = '774a1dee2b3a3d6c64c0e47124d3ac7522ae5c57e1fef1c4abb1b3dd63bffee6';
var destinationAddress = '44241d4e6a0fd2acff819478a87b7cdfe7963468';
var document = Buffer.from('Hello Crypto! ' + Math.random().toString());

var documentHash = ethproof.hashDocument(document);
var txHash = ethproof.publishProof(privateKeyHex, destinationAddress, documentHash);

The above examples provide no JSON RPC URI to the publishProof(...) call. As such they default to localhost and default port. If you would like to use Infura or any other custom URI pass it as the final parameter. For example:

var txHash = publishProof(privateKeyHex, destinationAddress, documentHash, 'https://rinkeby.infura.io/');

If the transaction can not be sent, an error will be thrown and can be handled with try {...} catch (err) {...}

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

Use npm test to run linting and tests.

Mining

If you need Ethereum to work with, consider Ethereum mining with WinEth

Author

ethproof © Stefan Gordon, Released under the MIT License.
Authored and maintained by Stefan Gordon with help from contributors (list).

github.com/stefangordon · GitHub @Stefan Gordon · Twitter @stefangordon